Watford at a glance
- Postcode districts
- WD1, WD17, WD18, WD19, WD24, WD25
- Population
- about 125,707 (GeoNames)
- Council area
- Watford Borough Council
- Building approval
- Watford Borough Council building control, or a registered building control approver
- Nearest main town
- Slough, about 13 miles
- Guide price region
- East of England (+5% on West Midlands rates)
Why choose a green roof in Watford?
Rainwater from flat roofs in Watford runs off quickly in heavy showers. A green roof holds some of that water back and releases it more slowly, which is one reason some owners and developers choose one. The flowering sedum also draws in bees and other insects.
In and around Watford, flat roofs are typically found on terraced streets with flat-roofed rear kitchens and bathrooms, and on bungalows with flat-roofed side extensions and dormers. The East of England is the driest part of Britain, with parts of the Anglian region around 630 mm a year, so summer heat and UV, not rainfall, do most of the ageing on a felt roof.
How much does a green roof cost in Watford?
For Watford we use East of England rates: £4,650–£8,500 is the guide for a 20 m² insulated extension roof finished as a sedum green roof, VAT included. The fixed price comes after a free survey for new and replacement roofs.
| Job | Guide price inc VAT |
|---|---|
| Extension (20 m²), EPDM with sedum green roof | £4,650–£8,500 |
| Extension (20 m²), EPDM, new deck + insulation | £2,950–£5,150 |
Can a green roof go on my existing flat roof?
Only if the existing waterproofing is sound, root-resistant or protected by a root barrier, and has plenty of life left. In most cases it makes more sense to lay a green roof as part of a replacement.
Once the sedum, substrate and drainage layers are down, the membrane underneath is hard to inspect and expensive to repair, because the green layers have to be lifted to get to it. Putting a green roof on an ageing covering risks paying for the greenery twice. Our repair or replace guide helps you judge whether your current roof is a sensible base.
As for planning, re-covering a house roof normally needs no application if its appearance doesn't change materially. Because a green roof does change how a roof looks, check with your council, especially for listed buildings, conservation areas and roofs that are easily seen. The planning guide has more.
What's included?
- Structural check of joists, deck and supports
- Pre-grown sedum blankets laid and watered in
- Drainage layer, filter and lightweight growing medium
- Gravel strips kept clear around edges and outlets
Building regulations in England
Replacing more than half of a flat roof over a heated room usually counts as renovating a thermal element, so the roof is insulated to around 0.16 W/m²K where that's technically and economically feasible, and the work is notified to building control: the council or a registered building control approver, unless a registered competent person self-certifies it. A roof on a new extension is built to 0.15 W/m²K. Patch repairs, and most unheated detached garages, don't trigger the upgrade. Structural changes, or a new covering that adds 15% or more to the roof's weight, also need approval. More on the rules.
Which nearby areas do we also cover?
- Bushey · 2 mi
- Rickmansworth · 4 mi
- Borehamwood · 5 mi
- St Albans · 7 mi
- Hemel Hempstead · 7 mi
- Chalfont Saint Peter · 8 mi
Green and sedum roofs in Watford: questions
Do you cover Watford?
Yes. Watford is part of our Hertfordshire coverage, including postcode districts WD1, WD17, WD18, WD19, WD24, WD25. Surveys and roofs are carried out by vetted roofing teams working under S&K Property Investments and Improvement Ltd.
Who checks building regulations for a flat roof in Watford?
Where the work needs approval it goes to Watford Borough Council building control, or a registered building control approver. We tell you at the survey whether your job needs it and deal with the paperwork as part of the quote.
How much does a green roof cost in Watford?
£4,650–£8,500 for a 20 m² insulated extension roof finished as a sedum green roof, at East of England guide rates including VAT. The fixed price comes after a free survey for new and replacement roofs.
Does a green roof leak more than a normal flat roof?
No, as long as it is built correctly. The waterproofing beneath is what keeps water out, and the green layers protect it from sun and weather. The main risk is building it on a weak or ageing membrane.
Can a green roof have a rooflight in it?
Yes. The rooflight sits on a raised upstand with a gravel strip around it, so the planting stays clear of the glazing and the upstand stays visible and dry.